wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<note><desc>world</desc><name>79</name></note | <note><desc>world</desc><name>79</name></note> | Add closing >. | XML |
<input type='text' value='message'> | <input type='text' value='message' name='status'> | Add name attribute. | HTML |
a == '27' | a === 27 | Use strict equality. | JavaScript |
int foo = 'hello'; | String foo = 'hello'; | Type mismatch. | Dart |
$values[1] | if ($values.Count -gt 1) {{ $values[1] }} | Check bounds. | PowerShell |
for (temp in arr) | for (temp of arr) | for...in iterates keys. | JavaScript |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
for c in range(37)
print(c) | for c in range(37):
print(c) | Colon after for. | Python |
let c: number = 'test'; | let c: string = 'test'; | Fix type. | TypeScript |
let temp: number | null = null; temp.toFixed(2); | let temp: number | null = null; if(temp!==null) temp.toFixed(2); | Null check. | TypeScript |
<br></br> | <br> | Self-closing. | HTML |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
temp = data | temp = 'data' | Quote strings. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
bar = 39 | bar=39 | No spaces. | Shell |
test | test() | Add parentheses. | Swift |
println('data') | println("data") | Double quotes. | Scala |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
const y = 88; y = 57; | let y = 88; y = 57; | Cannot reassign const. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let count = 97; let count = 33; | let count = 97; count = 33; | Duplicate declaration. | JavaScript |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
if (a = 68) {{}} | if (a === 68) {{}} | Use === for equality. | JavaScript |
while y > 35
y -= 1 | while y > 35:
y -= 1 | Colon missing after while. | Python |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
DELETE FROM users WHERE age=86 | DELETE FROM users WHERE age=86; | Add semicolon. | SQL |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(60); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(60); | Correct. | Node.js |
<p>world <b>hello</p></b> | <p>world <b>hello</b></p> | Nest properly. | HTML |
let c = 35; c += 1; | let mut c = 35; c += 1; | Need mut to modify. | Rust |
disp('world') | disp('world') | Correct. | MATLAB |
val temp: Int = 'value' | val temp: String = 'value' | Fix type. | Kotlin |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if (a = 87) | if (a == 87) | Use ==. | Scala |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(21); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(21, () => console.log('listening')); | Add callback. | Node.js |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
list[61] | if (list.indices.contains(61)) list[61] | Check index. | Kotlin |
assert num > 53 | assert num > 53 | Correct. | Python |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
if count = 85: | if count == 85: | Use == for comparison. | Python |
let data = 90; | let data = 90; | Correct. | JavaScript |
fn render() -> i32 {{ 30 }} | fn render() -> i32 {{ 30 }} | Correct. | Rust |
List(23,88,13) | List(23,88,13) | Correct. | Scala |
let vec=vec![100,27,18]; let first=&vec[0]; vec.push(39); | let mut vec=vec![100,27,18]; let first=vec[0]; vec.push(39); | Copy instead of reference. | Rust |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
int[] arr = new int[75];
arr[75] = 5; | int[] arr = new int[75];
if (75 < arr.length) arr[75] = 5; | Check bounds. | Java |
<hr></hr> | <hr> | Self-closing. | HTML |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (x = 3) {{}} | if (x == 3) {{}} | Use ==. | Java |
<note name='data'/> | <note name="data"/> | Double quotes. | XML |
else
print('data') | else:
print('data') | Colon after else. | Python |
for (int i=0; i<5; i++) {{}} | for (int i=0; i<5; i++) {{}} | Correct. | Java |
UPDATE orders SET status='info' WHERE role=85 | UPDATE orders SET status='info' WHERE role=85; | Add semicolon. | SQL |
[28, 36, 84 | [28, 36, 84] | Close bracket. | Python |
// comment | /* comment */ | Use /* */. | CSS |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
if ($index = 68) | if ($index == 68) | Use ==. | Perl |
#footer {{ color: green; }} | #footer {{ color: green; }} | Correct. | CSS |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
let text = String::from("data"); let borrow=&text; text.push_str("!"); | let mut text = String::from("data"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
arr.forEach(function(val) {{ console.log(val); }}) | arr.forEach((val) => {{ console.log(val); }}) | Arrow functions are cleaner. | JavaScript |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
WHERE name = '41' | WHERE name = 41 | Don't quote integer. | SQL |
if ($num = 18) {{}} | if ($num -eq 18) {{}} | Use -eq. | PowerShell |
if b = 7 | if b == 7 | Use ==. | Go |
function baz(b)
print(b)
end | function baz(b)
print(b)
end | Correct. | Lua |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
var x int | var x int | Correct. | Go |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
70result = 10 | result70 = 10 | Variable cannot start with digit. | Python |
class Person {{ int num; }}; | class Person {{ public: int num; }}; | Make public. | C++ |
{{"age":"info" "age":86}} | {{"age":"info", "age":86}} | Add comma. | JSON |
const val; | const val = 41; | Initialize const. | JavaScript |
[16, 70, 33 | [16, 70, 33] | Close bracket. | Ruby |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
name: value
age: 73 | name: value
age: 73 | Correct. | YAML |
x := 97 | x := 97 | Correct. | Go |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
yield index | yield index | Correct yield. | Python |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
let mut val=17; let ref1=&mut val; let ref2=&mut val; | let mut val=17; {{ let ref1=&mut val; }} let ref2=&mut val; | Only one mutable borrow. | Rust |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
SELECT id role FROM orders; | SELECT id, role FROM orders; | Add comma. | SQL |
def render(val):
return val + 1 | def render(val):
return val + 1 | Correct. | Python |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
if (index = 25) {{}} | if (index == 25) {{}} | Use ==. | Kotlin |
SELECT * FROM users WHRE name=38; | SELECT * FROM users WHERE name=38; | Fix WHERE. | SQL |
let foo: Int = 'world' | let foo: String = 'world' | Fix type. | Swift |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
data[18] | if data.indices.contains(18) {{ data[18] }} | Check index. | Swift |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
val b = 60; b = 99 | var b = 60; b = 99 | Use var for reassignment. | Scala |
'hello' + 64 | 'hello' + 64.to_s | Convert int. | Ruby |
print('info') | print('info') | Correct. | R |
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